GRID
- Synthesis -
ADINA RIPOSAN
Department of Applied Informatics
Military Technical Academy
Bucharest, 2006
Grid Definitions,
Properties & Categories
Military Technical Academy
Bucharest, 2006
The Grid Dream
Grid takes its name from analogy with
electrical power Grid:
 electricity on demand via wall socket
 source unknown but reliable
 transparency and resilience are keys to its
success
The Grid dream is to allow users to tap into
resources off the internet as easily as electrical
power can be drawn from a wall socket
- imagine …
Military Technical Academy
Bucharest, 2006
To make this happen, what do we need:

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Pervasive deployment of infrastructure
Security
Accountancy i.e pay for what you use…
Transparent access
• The user is not aware (and doesn’t care) what
computing resources are used to solve their problem
… just as one has with power.
Military Technical Academy
Bucharest, 2006
There are many attempts for the accurate definition
of the Grid.
Grid is currently defined as a distributed, high
performance computing and data handling
infrastructure that incorporates geographically
and organizationally dispersed, heterogeneous
resources (computing systems, storage systems,
instruments and other real-time data sources,
human collaborators, communication systems)
and provides common interfaces for all resources,
using standard, open, general-purpose protocols
and interfaces, and allows for a shared access
among them. It is also the basis and the enabling
technology for pervasive and utility computing due
to the ability of being open, highly heterogeneous
and scalable
(Ian Foster, “What is the Grid? A Three Point Checklist”, Grid
Today, July 20, 2002)
Military Technical Academy
Bucharest, 2006
Grids are basically considered to have
three main properties:


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they coordinate resources that are not subject
to centralized control;
they use standard, open, general-purpose
protocols and interfaces;
they deliver non-trivial qualities of service
(QoS).
Military Technical Academy
Bucharest, 2006
Grid systems are generally classified in
three categories:

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Computational Grid: is a distributed set of resources
dedicated to aggregate computational capacity, a virtual
metacenter that aggregates the processing power from a
distributed collection of systems, integrating large amount
of Grid computing resources.
Data Grid: is a collection of distributed resources
dedicated for processing and transferring large amounts
of data, for large scale data processing and management
that require the participation of widely dispersed research
communities; while computational grids are more suited
for aggregating resources, data grids focus on providing
secure access to distributed, heterogeneous pools of data.
Access Grid: is the human interface of computational Grid
and Data Grid.
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Bucharest, 2006
The key to this integration is the concept of
Virtual Organizations that facilitate the
establishment of cross-organizational sharing
relationships.
=> The Grid can be viewed as an infrastructure to
support Virtual Organizations with a single
sign-on mechanism, that enable advanced
forms of cooperative work.
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Bucharest, 2006
The users of the Grid can be organized
dynamically into a number of
Virtual Organizations (VOs),
consisting of
resources, services, and people
collaborating across
institutional, geographical, and political
boundaries,
each with different Policy Requirements.
Military Technical Academy
Bucharest, 2006
This sharing is, necessarily, highly protected,
with resource providers and consumers
defining clearly and carefully

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what is shared,
who is allowed to share,
the conditions under which sharing occurs.
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Bucharest, 2006
Globus Toolkit
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Bucharest, 2006
The Globus toolkit (GT) is the de facto open source
toolkit for Grid computing, containing a set of
tools which enable applications to handle
distributed heterogeneous computing resources as
a single virtual machine.
Globus toolkit uses standards wherever possible and
well-defined interfaces that can be integrated into
applications in an incremental fashion.
Some of the standards were achieved through the
GGF - the Global Grid Forum.
The Globus project is a U.S. multi-institutional
research effort.
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Bucharest, 2006
SEVERAL VERSIONS of the Globus toolkit have been
released so far:
Globus has evolved from the I-Soft system, through
version 1 (GT1) to version 2 (GT2) and the focused
has moved:
• from supporting just high-performance applications
• towards supporting more pervasive services that can
support virtual organizations.
Starting with the GT version 3.x (released 2002) the
functionality is exposed as:
• a collection of virtual Open Grid Services Architecture
(OGSA) services.
Further on, GT version 4.x (2004) consists of a
transformation:
• from GT3 OGSI-based services
• to GT4 WSRF-based services and associated
documentation
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Bucharest, 2006
The Globus toolkit essentially consisted of 4 elements:

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Security: to provide authentication, delegation and
authorization, based on GSI - Grid Security Infrastructure
Information Services: to provide information about Grid
services, based on MDS - Monitoring and Discovery
Service, which in turn consists of three main components:
• GRIS (Grid Resource Information Servers),
• IP (Information Providers),
• GIIS and (Grid Index Information Services).

Data Management: involves accessing and managing data,
it consists of three distinct components:
• GridFTP (extended version of the IETF’s FTP),
• Data Replication (Replica Catalog and Replica Management
tool),
• GASS (Global Access to Secondary Storage).

Resource Management: to allocate resources provided by
a Grid, based on Globus Resource Allocation Manager
(GRAM).
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Bucharest, 2006
Applications
HEP, Biology, Astrophysics ..
Application
Toolkits
Portals, remote steering,
data grids, remote visualization ...
Grid APIs
Globus: security, resource
management, information services,
events, data management ...
Grid Fabric
Computers, storage, sensors,
network and their
associated services
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Bucharest, 2006
History of Grid Computing
Military Technical Academy
Bucharest, 2006
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First Generation:
Early Metacomputing environments, such as FAFNER
(http://www.npac.syr.edu/factoring.html) and the I-WAY
Second Generation:
• Core Grid technologies like the Globus toolkit (www.globus.org –
later) and Legion (http://legion.virginia.edu/download/)
• Distributed object systems e.g. Jini (www.jini.org) and CORBA
(www.corba.org)
• Grid resource brokers and Schedulers e.g.

Condor (http://www.cs.wisc.edu/condor/) and
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SGE (http://wwws.sun.com/software/gridware/sge.html)
• Integrated systems including Cactus (cactuscode.org), DataGrid,
UNICORE (www.unicore.org) and P2P Computing frameworks e.g.
Jxta (jxta.org)
• Application user interfaces for remote steering and visualization
e.g. Portals and Grid Computing Environments
The Third Generation:
• introduction of a service-oriented approach (e.g. OGSA)
• Increasing use of metadata (giving more detailed information
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describing services)
Bucharest, 2006

Today, in the evolution of Grid computing we are
focusing more on service-based architectures, such as
Web services,
=> specifications have been derived from these
primitives, such as OGSA and implementations in the
form of WS-RF.

Such specifications represent clear moves in support
of globally accepted standards, which aims to reach
the ultimate Grid goal of global ubiquitous utility
computing.
Such standards also allow the cross-fertilisation of a number of
technologies with Grid computing,
in particular P2P computing, which has evolved through
Internet grass roots culture programming of file sharing
systems, such as Napster and more notably Gnutella with its
fully decentralised design.
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Bucharest, 2006
However, the question will always exist on ‘if’ and ‘why’
a Grid solution should be adopted in comparison to
any other non-Grid solution.
It should be noted that Grid is not meant to be the
‘panacea’ to all the problems, and it is not expected to
provide all the answers.

It should be considering merely as a technology that
aims to provide more efficient solutions to some of
the problems,
 and can be the ideal solution for many large scale
applications that are of dynamic nature and require
transparency for users.
Military Technical Academy
Bucharest, 2006